Syria, racked by civil war, and Nicaragua were the only two nations outside the 195-nation pact when it was agreed in 2015. Nicaragua's left-wing government, which originally denounced the plan as too weak, signed up last month.

Commander Ahmed Abu Khawla told Reuters that the Conoco gas field was the first of its kind taken by the Syrian Democratic Forces (SDF), an alliance of Kurdish and Arab militias, since it began an offensive earlier this month to capture the eastern province.

The latest attack by the trump administration on Syrian air base may have led to a 2 percent jump in global benchmarks in intra-day trade, experts say the current oil market fundamentals of an oil glut will continue to weigh over short term supply disruptions to keep prices under check.